1. Field of the Invention
The present invention relates to a water pump.
2. Description of the Related Art
For example, a water pump for supplying cooling water to a fuel cell is installed in a fuel cell automobile or the like.
The water pump generally includes a pump section having radial impeller blades and a motor section for driving a rotational shaft for rotating the radial impeller blades (see Japanese Patent Application Publication No. 10-24192 (JP 10-24192 A)). The motor section is covered by a motor casing and has a motor for rotating the rotational shaft, bearings provided in front and rear of the motor, and so forth.
In the water pump, water supplied to the pump section may leak to the motor section side along a sealing section. Therefore, a measure is suggested such that a weep hole is provided on the motor section side of the pump section (see Japanese Patent Application Publication No. 2004-162609 (JP 2004-162609 A)).
However, even if the weep hole described above is provided, water leaking from the pump section may deposit, for example, in a vicinity of the bearing on the front side on the motor section side. As a result, when air expansion or compression occurs due to temperature fluctuation or the like caused by heat in the motor casing and the air in the motor casing is rapidly compressed, the water deposited in the vicinity of the bearing may enter the motor of the motor section from the bearing. If water enters the motor, failure of the water pump may occur.